The present invention is directed to a casing hanger assembly for use with containment well cellars of the types described and claimed in U.S. Pat. Nos. 7,637,692, 7,987,904, 8,127,837, 8,256,505, and 8,485,250 each of which is hereby incorporated by reference.
The containment well cellars described and claimed in the above noted patents are becoming increasingly recognized for their environmentally-friendly features, as well as for their advantages in well installation and operation. It is among the objects of the present invention to provide accessorial equipment which will further enhance the advantages of this family of sealed well cellars. It will be understood that the features of this invention may be equally of value when employed with other existing and as-yet-to-be-developed well cellars, or simply to hang casing in applications where a well cellar is not being used.
Currently in the industry, casing hangers, both the mandrel and slip types, are used to suspend the weight of a second inner casing on a first outer well casing. This may be done before or after the inner well casing is cemented in place. Existing casing hangers are a part of the wellhead assembly. Typically, when weight in the form of the blow-out-preventer (BOP) or wellhead assembly is attached to the inner casing and, thereby, supported by the partially cured cement, this weight, in conjunction with vibrations associated with the drilling operations, will cause shifting of the well casings and cracking of the cement. This breaks containment allowing migration of well fluids into the area around the wellhead, which contaminates the soil and can pollute the riparian ground water.
In addition, well operators often have a need to position the surface casing in a particular rotational orientation during installation. For example, in some situations the operator must turn the casing so that piping or valves attached to the surface casing are aligned with outlets on the well cellar or other piping installed at the well site. While the heavy machinery used to install the casing provides control in the vertical direction, it does not provide the ability to control the rotation of the casing as it is lowered into position. It would therefore be advantageous to develop a casing hanger system that causes rotation of the inner casing as it is lowered into a conductor pipe or outer casing, securing the casing in a preferred rotational orientation.